A scanning electron microscope (SEM) used to observe, inspect, or measure a sample using an electron beam, which is one of charged particle beams, accelerates electrons emitted from an electron source and converges onto a surface of the sample using an electrostatic lens or an electromagnetic lens for irradiation thereon. They are referred to as primary electrons. Incidence of the primary electrons generates secondary electrons (sometimes low-energy electrons may be referred to as the secondary electrons and high-energy electrons as reflection electrons, distinctively). By detecting the secondary electrons while deflecting and scanning the electron beam, it is possible to obtain a scanning image of a fine pattern and a composition distribution on the sample. It is also possible to form an absorption current image by detecting electrons absorbed by the sample.
Conventional methods of deflecting an electron beam are disclosed in, for example, Patent Documents 1 and 2. These Patent Documents aim to reduce a deflection aberration caused by the deflection of the electron beam by overlapping a field of an electromagnetic deflector and a field of an electromagnetic lens.